Mirador I believe it was yellow fever that plagued the French troops rather than malaria (though that existed certainly and still does in some places along the border). There is no such thing as immunity to malaria.
Ironically malaria was almost eradicated in the 20th century but extermination was halted before it could achieve this end.
PS: let me amend that: one can develop immunity to certain forms of malaria but the most dangerous kind, the fatal form, prevalent nowadays in AFrica, at least from what I have read, does not admit of such protection. ALso the malaria bug is very transmutable so it resists efforts to vaccinate against it. It is a major killer globally.
Ironically malaria was almost eradicated in the 20th century but extermination was halted before it could achieve this end.
PS: let me amend that: one can develop immunity to certain forms of malaria but the most dangerous kind, the fatal form, prevalent nowadays in AFrica, at least from what I have read, does not admit of such protection. ALso the malaria bug is very transmutable so it resists efforts to vaccinate against it. It is a major killer globally.